Abstract : A signal processing circuit for producing a warhead firing pulse when the warhead is in a position to cause maximum target damage in a missile, target encounter. The received doppler signal is processed through filter circuits and a first band-pass amplifier. A second bandpass amplifier tuned to pass a narrow portion of the frequency spectrum above the doppler signal is connected in parallel with the first amplifier and its output signal is used to vary the threshold bias to compensate for the presence of extremely noisy signals. (Author)